Monday, June 30, 2008

The Truth of evolution

I was recently listening to Dr. Al Mohler’s radio program (via MP3), whom I normally have the highest respect for, but the topic this time was the conflict of evolution and the Christian worldview. He was addressing how some so called Christians’ subscription to evolution was evidence that they were going wishy-washy on Genesis or true Biblical Christianity. I agreed with a lot of what he said, provided I interpreted his use of “evolution” as Darwinism. So I just want to clear the air (or muddy it as some will likely see it) on what is true and scientific about evolution and what is not.

My main concern is in our use and understanding of the jargon that goes along with any discussion of this kind. Equivocation on what evolution actually is, can and does lead to misunderstandings which results in people of faith and people of science talking past each other rather than with each other.

Evolution is a theory which hypothesizes the process of descent with modification to account for diversity of organisms. This process posits the role of natural selection in filtering for preferable phenotypes which are distributed in a given population because of genetic variation and random mutations produced during reproduction. Homology of anatomical or morphological features (body parts and functions) is now known to be explained by parallel homology of genetic material (DNA) between or among species. Common ancestry is considered the explanation for such homologous features.

This may be surprising to some of you, but I agree with all the above but the last sentence. Let’s take a closer look at some of the key terms and ideas above to see why.

1. Descent with modification – basically means that offspring are not identical to each other or their parents, (come on, Jacob and Esau teach us this!). There is always some shuffling of DNA and genes from one generation to the next. NOTE: more recent discoveries of horizontal gene transfer in prokaryotes have modified this aspect to include obtaining genetic material from non-parental sources like plasmids, viral transposons or other HGT mechanisms.

2. Natural Selection – this is the process whereby certain traits or phenotypes are preserved in the gene pool due to selective advantages or adaptations to habitation, limited resources or competitors/predators. This is true observation.

3. Random mutations (Unguided Heritable Variation) – when DNA gets replicated, sometimes mistakes are made; these mistakes can be silent, harmful, fatal, or more rarely, advantageous (as in the case of antibiotic resistance of some bacteria). True observation.

4. Homology – this just means “similarity”. It used to apply to morphological features like skull shape or limb structure. It now includes similarity of DNA sequences. True observation.

5. Universal Common Ancestry – this is the unifying principle of evolution; not just that we as humans share a common ancestor, which is reasonable (even Biblical!), but that all organisms are distantly related. Theory, not a proven observation.

So I think it’s important that Christians are informed when commenting on evolution as it impacts the Christian worldview or what gets taught in schools, so that Christians don’t needlessly raise contentions between faith and science where they are unwarranted. Most of the observations above (#1-4) are real and true and thus are not in conflict with Biblical Christianity. Furthermore, they can and do contribute to Intelligent Design (ID) theory as an alternative scientific theory to common ancestry (more on ID theory later).

So if you go back to my initial definition of evolution, confusion arises when some people see that evolution does account for some biological diversity but then extrapolate that it can account for all biological diversity (microevolution vs. macroevolution, if you will). It behooves us as Christians to recognize truth no matter what the source and use words with an understanding for whats behind them.